This invention relates to an exposure control device for an electronic photographing apparatus, which controls exposure when photographing an object using a solid state image sensor.
An electronic photographing apparatus for photographing an object using a solid state image sensor constituted by a charge transfer device (CTD), e.g., a CCD or a BBD, is well known as a solid state video camera or an electronic still camera. In such electronic photographing apparatus the exposure is controlled by varying the period of integration of the charge stored in the CCD, for instance. The integration period is set by determining the timing of the on-off operation of a transfer gate in the CCD from the relation between a shutter release pulse and a exposure signal. Therefore, the control of the CCD, i.e., the horizontal and vertical scanning control, and the on-off control of the transfer gate are not synchronized, and a shutter speed faster than 1/60 sec. cannot be set accurately. Further, the CCD control and the transfer gate on-off control are not synchronized to the rotation of the magnetic disc. Therefore, the record start points of individual frames are not aligned on the recording disc, so that a frame cannot be readily retrieved in playback.